Advance Reservation

BC Project: FY09-01
Date of Policy: 23 Feb 2009
Last Updated: 08 Dec 2020 (see Revision Log)

The Advance Reservation Service (ARS) provides advance scheduling on all HPCMP user-accessible systems. ARS uses the system scheduler to perform the advance scheduling. This policy provides a consistent ARS framework for access, usage, and capability across all DoD Supercomputing Resource Centers (DSRCs).

Access to the ARS is web-based with user authentication for access provided through HPCMP designated authentication methods.

The key capabilities of ARS allow users to:

  • Make a reservation for one or more users, starting at a specific date/time, for a specific number of nodes (total cores requested is determined based on cores-per-node of the selected architecture), lasting for a specified number of hours. License reservations can be made in ARS for shared-license-buffer (SLB)-controlled applications (Abaqus, Accelrys, Ansys-CFD, Gasp, LS-Dyna, Matlab, and Star-CCM). Users needing any of these licenses should request a license reservation at the time the nodes are reserved. Requests for licenses for individual PBS jobs submitted to run in the ARS reservation session are unnecessary since the licenses are already reserved.
  • Perform a job slot search, in which the user provides a set of job slot requirements and ARS returns possible start dates/times
  • Cancel a reservation
  • View an online Reservation Calendar

An ARS User's Guide is available at

The total number of compute nodes available for ARS plus the number of compute nodes dedicated to Dedicated Support Partitions (DSPs) on each system will not exceed 15% and will not be less than 10% of the number of reservable compute nodes on that system. To ensure availability of at least 10% of the compute nodes for ARS use, the total number of compute nodes for DSP use will not exceed 5% of the compute nodes on any system. These percentages may be adjusted on a system-by-system basis during unusually high utilization periods upon mutual agreement by the Associate Director for HPC Centers and the Associate Director for Resource Management. Any adjustment agreed upon in this manner must be announced to the user population at least one month before implementation, and any reservations made before the announcement must be protected. In order to ensure efficient use of compute nodes available for ARS, an effective backfill activity must be implemented on each system for these nodes.

A user is allowed to have up to four active reservations on a specific system at any given time. Applicable limits, including the total nodes in use by one user across all that user's active reservations, are shown in the table below.

ARS Reservation Class Limits
Earliest Submit Time Latest Submit Time Maximum
Maximum Number
of Active
Reservations per
Maximum Number of
Compute Nodes in
Active ARS Use Per
Three months prior to reservation start Four days prior to reservation start 168 hours Four 50% of nodes available to ARS

Once a reservation is submitted using the web-form, an email is sent to the user that provides the reservation identifier and a description of how to submit a job using the reservation identifier.

Allocation Billing

Users must provide a Subproject ID as part of the ARS reservation process. However, for batch jobs submitted against the reservation, the Subproject ID in the batch job will be the project against which allocation charges will be made for that job. Any residual core-hours unused by batch jobs during the reservation time slot will be charged against the reservation Subproject ID. Checks are performed prior to the acceptance of a reservation to ensure the reservation does not cause a subproject to exceed its allocation.

Cancellation and Reimbursement Policy

Reservations may be canceled with no allocation charges up to 8 hours prior to the start-time of the reservation. Users will be charged the full reservation allocation (number of cores times reservation duration in hours) for reservations canceled less than 8 hours before the start-time of the reservation. In the event a reservation cannot be used in its entirety or is only partially used due to a system problem, reimbursement of allocation core-hours will be granted by center management on a case-by-case basis.

Notice: Currently, ARS uses the PBSpro scheduler to perform advance reservation. In the near future, other job schedulers may also be used to perform advance reservation.

Revision Log
Date Revision
08 Dec 2020Replaced PBS scheduler by a generic job scheduler
28 Jun 2018BC Team Audit – Revised upper limit on ARS nodes, included DSP nodes in the limit, eliminated the category of short-lead-time reservations, included software license reservations, and other minor modifications
05 Oct 2016Reworded "total number of computation nodes"
23 Jun 2016BC Team Audit
01 May 2014BC Team Audit
02 Apr 2012BC Team Audit
05 Aug 2010Instituted across all six DSRCs
28 May 2010Submit Time description for Short-Lead Time modified